Not Applicable
Not Applicable
1. Field of the Invention
The present invention is in the field of cryosurgical catheters.
2. Background Art
In the treatment of various medical conditions, it is sometimes beneficial to apply an extremely cold temperature at one or more selected, isolated locations in or near a selected organ in the patient""s body. As an example, it can be beneficial in the treatment of cardiac arrhythmia to apply cryosurgical temperatures at selected locations in the patient""s heart, to create localized areas of necrotic tissue. Similarly, it can be beneficial to apply extremely cold temperatures at selected locations in other organs, or in a vascular system of the patient. The application of extremely cold temperatures can be achieved by inserting a flexible cryosurgical catheter through a vascular system to the desired location. The flexible catheter can have a heat transfer element at or near its distal end. The heat transfer element can be cooled to a cryosurgical temperature and placed in contact with a selected area of biological tissue.
It would be desirable to facilitate the application of cold temperatures by devising an apparatus with the ability to flex the tip of the cryosurgical catheter in a desired direction, to assist in guiding the catheter through a tortuous path to the selected location in or near a selected organ, or in a vascular system.
According to certain embodiments of the invention, a surgical device is provided for applying cold temperatures at locations within the human body, via minimally invasive techniques. More specifically, the device may comprise a deflectable catheter, passable through the larger blood vessels and cavities of the heart, having a distal tip which can be deflected by remotely located means. The apparatus has conduits for the delivery and removal of refrigerant fluids within the catheter, and conductors for the monitoring of temperature and electrical impulse. A proximally located handle has a mechanism for activating the deflection of a distal catheter tip in a single plane. In certain embodiments, a flexible multiple conduit tubular vessel attached to the handle terminates in a dual channel quick connect plug for interfacing the catheter with a cryogenic fluid supply unit.
The catheter may have a torque transmitting tubular member extending from the handle to a distally located flexible tubular segment which, in turn, terminates in a high thermal conductivity tip. A deflection mechanism in the handle may manipulate the curvature of the distal flexible tubular segment of the catheter, and a braking or locking mechanism in the handle may be used to maintain a set curvature of the tip, with the tip deflection being in a predefined plane. A portion of the deflection mechanism in the handle insures that the axial tension imposed to effect deflection of the catheter tip is not transferred to the catheter shaft, thereby preventing transmission of force to the shaft. A mechanism is also incorporated into the handle to aid in the straightening of the distal tip section of the catheter, once deflection is released. A tensioning mechanism maintains a user adjustable, relatively constant tip deflection force throughout the range of motion.
Another feature that may be provided in the catheter is a device for monitoring interior catheter pressure near the catheter tip region. The conduits for refrigerant fluid delivery and removal, and the conduit for pressure monitoring are separated from the deflection mechanism in the handle, thereby relieving the need to hermetically seal the handle.
The novel features of this invention, as well as the invention itself, will be best understood from the attached drawings, taken along with the following description, in which similar reference characters refer to similar parts, and in which: